In the NGN proposed by the International Telecommunication Union (ITU-NGN), each transport layer function entity (transport resource enforcement function entity (TRE-FE) or policy enforcement function entity (PE-FE)) actively or passively transmits network topology and resource information to the transport control layer function entity (transport resource enforcement function entity (TRC-FE)) in time and accurately via an Rc interface.
The TRC-FE creates network resource status data according to the gathered topology and resource information, and performs resource admission control and path selection on a session according to the network resource data. The locations of the interfaces on which the information is transmitted from the transport layer FE (TRE-FE) to the transport control layer FE (TRC-FE) are the Rc (not shown in the drawing) and Re in FIG. 1 (TISPAN).
In the current Rc-related interface standards and drafts (mainly comprising Y.2111 RACF, Q.3304.1 COPS-PR Rc and Q.3304.2 SNMP Rc) defined by the ITU-T NGN, the information transmitted by the transport layer FE to the transport control layer FE mainly comprises network topology status information and its variation and bandwidth utilization status information of each link in the network.
FIG. 1 is the block diagram view of TSPAN NGN in the art, which comprises resource and admission control system (RACS), service-based policy decision function (SPDF), border gateway function (BGF), general-resource and admission control function (x-RACF), resource control enforcement function (RCEF), network attachment sub-system (NASS), application function (AF), user end (UE), basic transport function (BTF), while in TISPAN (ETSI ES 282 001 V1.1.1 (2005-08) and draft ETSI ES 182 019 V0.4.1 (2007-02)).
There is no definition relating to the collection of the network resource information in prior TSPAN NGN.
The resource information defined by the current standard comprises: network topology and variation status information and network link bandwidth utilization status information. The information is the very basic information for performing resource admission control and can only be used to perform basic, coarse grained and single dimensional resource admission control, that is, the admission control is performed according to the available bandwidth of the link in the network. However, the NGN supports very abundant services, and the sessions of some real time services have particular requirements on delay, delay jitter or packet loss ratio. In this situation, using the current network resource information can not realize accurate resource distribution and path selection.
On the other hand, an NGN transport network should be a network able to support various traffic classes, and provide different service capabilities to different traffic classes. Similarly, in order to exactly reflect the status of the network resource utilization, each transport layer function unit should transmit the status of network resource relating to each traffic class to the transport control layer function unit, however, it has not yet been realized in the prior art.